Rendering images and movies

- Rendering is where we create our final images. Rendering can be thought of as a form of virtual photography. We set up our 3D scene with virtual lights and cameras, then we render an image. Just like photography, lighting is a very important component. 3D applications have a number of ways to add lights to the scene. The first is to place virtual lights in the scene. These tend to mimic the lights found in a photographer's toolkit, such as spotlights or point lights. These lights can then be adjusted for brightness and color, among others. One great thing about virtual lights is that they don't have to obey the laws of physics. You can control whether or not a light casts shadows, and even control which objects it does and does not illuminate. This makes adjusting lighting very precise. Another way to create light is with image-based lighting. A high-resolution and high-bit-depth image is placed around the scene. This casts light into the scene. Image-based lighting is often used to create realistic environmental lighting. Indirect lighting is also important. This is incidental light that bounces off of one object and onto the others in the scene. This is typically created using tools such as Global Illumination or Ambient Occlusion, and can add realism and softness to a scene. Another form of indirect lighting is Caustics, which mimics the interaction of reflected and refracted light on surfaces. Of course, light is nothing without a camera to photograph it. 3D software allows for virtual cameras to be placed in the scene. These can mimic real-world cameras, complete with lenses and f-stops. Effects such as depth-of-field can also add extra interest to the scene. The rendering process often requires a lot of test renders. To speed up the process, many renderers offer progressive rendering, which gradually refines the image. Rendering often happens as a batch process. A network of computers each render frames to get the work done quickly. When creating computer graphics, if it looks good, it is good, and rendering helps makes your images look as good as possible.